There are several shortcomings in current video surveillance systems that need to be overcome for widespread use of automatic detection and collection of relevant video data in response to scene stimulus without the need of a human operator present. When viewing a scene from a video camera a large amount of data is generated. The vast amount of data created produces a data reduction problem. Automatically detecting and accurately and reliably collecting image information of a moving object using a motion video camera is a difficult task. This task is made even more difficult when trying to detect, track and maintain camera line-of-sight using a single motion video camera without requiring human intervention.
U.S. Pat. No. 5,473,369 (Abe) describes the use of a camera to detect and track a moving object without using conventional block matching. In the system described in Abe single object tracking is performed only after an object is placed within a frame on a screen; however, there is no user input device for manual target selection Moreover, Abe does not provide for camera movement to maintain line-of-site.
Other prior art solutions provide for image stabilization for a camera in arbitrary motion without object tracking functionality. U.S. Pat. No. 5,629,988 (Burt) teaches electronic stabilization of a sequence of images with respect to one another but provides no tracking facility.
Still other prior art solutions control camera movement to maintain line-of-sight between camera and object but lack arbitrary motion compensation or do not provide for automatic and user selected object tracking. U.S. Pat. No. 5,434,621 (Yu) teaches a method for automatic zooming and automatic tracking of an object using a zoom lens but does not provide for reorienting the camera's line-of-sight.
Many prior art system in the field lack optical zoom for maintaining object size within field-of-view. Efforts have been made to simultaneously support near field and far field tracking using two cameras.